Some of these printing tomes are encyclopedic and can be measured by the pound as well as page count. Some are more instructional in nature. It’s difficult to single out any of the books in this list—they’re all quite good. But I’ve earmarked several as being essential guides for designers wanting to deepen their understanding of printing.
The Basics of Print Production, by Mary Hardesty (Graphic Arts Technical Foundation, 2002)
The Complete Guide to Digital Color: Creative Use of Color in the Digital Arts, by Chris Linford (Collins Design, 2004)
Fold: The Professional’s Guide to Folding, (2-Volume Set), by Trish Witkowski (Finishing Experts Group, 2002)
A painstakingly researched and wonderfully detailed (and readable) encyclopedia ...